I've got EB's 268 in my 84. I put it in when I did the rebuild and I opened up the exhaust at the same time. Truck is very peppy and I'm happy with the cam. As for being any louder, in the mornings when it's cold my truck sounds like a race truck loping along until it gets warmed up, (kinda like it!) <img src="/forums/images/graemlins/smile.gif" alt="" />, but once it's warmed up quiet as can be. Can't comment on the gas mileage, I have some carb issues that I havn't been able to resolve, runs too rich, so my mileage is for crap. <img src="/forums/images/graemlins/angry.gif" alt="" />